1. Field of the Invention
The present invention relates to an information processing device, and more particularly, to a cellular phone capable of performing a timer control operation in consideration of a display state of a display unit and a power saving.
2. Related Art
Wireless terminals such as a cellular phone, as a typical example of an information processing device, continuously save power without operating a main control unit by carrying out a designated operation (job) at the scheduled time, after elapse of a predetermined period, or at preset time intervals. To attain the power-saving function, a timer provided to the main control unit of the cellular phone is used. The timer periodically executes a predetermined operation after the elapse of a predetermined period or at preset time intervals.
There are two types of timers, a hard timer and a soft timer, which are used in combination while characteristics of these timers are utilized (see Japanese Unexamined Patent Application Publication No. 2005-110050, for example).
Examples of the hard timer include a constant-period hard timer that outputs signals at regular intervals and a hard timer such as a real time clock. Such a hard timer continues counting even if a CPU (Central Processing Unit) is in an “OFF” state (sleep state). Upon time-out, the hard timer sends an interrupt signal to the main control unit to notify a unit for running an application about the time-out. In contrast, the soft timer is updated in accordance with a program. If the CPU shows an “OFF” state (sleep state), the soft timer does not execute counting. When the CPU is turned on, it is determined whether a time-out has occurred. If the time-out has occurred, the timer notifies a unit for running an application about the time-out.
The cellular phone disclosed in Japanese Unexamined Patent Application Publication No. 2005-110050 change a period at which the timer generates a polling timing signal depending on an on/off state of the display unit of the cellular phone. Thus, when the display unit shows an “OFF” state, an intermittent operation cycle is lengthened to thereby reduce the power consumption.
A GUI (Graphical User Interface) is displayed, for example, on the display unit of the cellular phone by an application involved in display processing such as scrolling, blinking, or scrolling a marquee. If a soft timer is used for timer-based processing on the application for displaying the GUI, when the CPU is in the “OFF” state, the soft timer stops its operation and waits until the CPU is turned on in response to the next interrupt processing, and then, performs predetermined processing after time-out. Hence, if the CPU of the cellular phone is in an “ON” state, the GUI display processing is appropriately performed. In contrast, if the CPU is in an “OFF” state, the unit for running an application is not notified of the time-out, and the GUI display processing is not appropriately performed.
For this purpose, the following is conceivable. That is, the display unit of the cellular phone is not turned on/off in synchronism with the shift to an on/off state of the CPU. For example, even if the display unit is in the “ON” state, the CPU may be turned off under control. Assuming that such a control is applied to the cellular phone, the following problem would occur.
For example, when the display unit of the cellular phone is turned on, and any application executes GUI display processing such as blinking, if the CPU is shifted to an off state, a soft timer for appropriately executing the GUI display processing such as blinking does not work. As a result, even though the display unit of the cellular phone is turned on, the unit for running an application is not notified of the time-out, and the GUI display processing is not appropriately performed, so a user cannot view GUI contents.
To solve the above problem, the application for displaying the GUI might be controlled using a hard timer all the time irrespective of on/off state of the CPU. However, it is not desirable to execute the GUI display processing such as blinking even through the display unit is turned off and a user cannot view a displayed GUI screen from the viewpoint of saving power consumption.